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[ARM] 4814/1: RealView: Add broadcasting clockevents support for ARM11MPCore 

This patch adds dummy local timers for each CPU so that the board clock
device is used to broadcast events to the other CPUs. The patch also
adds the declaration for the dummy_timer_setup function (the equivalent
of local_timer_setup when CONFIG_LOCAL_TIMERS is not set).

Due to the way clockevents work, the dummy timer on the first CPU has to
be registered before the board timer.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas 2008-02-04 17:30:57 +01:00 committed by Russell King
parent 3e45999096
commit a8655e83fc
7 changed files with 69 additions and 17 deletions
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5
arch/arm/Kconfig
View File

@ -33,6 +33,11 @@ config GENERIC_CLOCKEVENTS
bool
default n
config GENERIC_CLOCKEVENTS_BROADCAST
bool
depends on GENERIC_CLOCKEVENTS
default y if SMP && !LOCAL_TIMERS
config MMU
bool
default y

10
arch/arm/kernel/smp.c
View File

@ -290,6 +290,11 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
local_irq_enable();
local_fiq_enable();
/*
* Setup local timer for this CPU.
*/
local_timer_setup(cpu);
calibrate_delay();
smp_store_cpu_info(cpu);
@ -299,11 +304,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
*/
cpu_set(cpu, cpu_online_map);
/*
* Setup local timer for this CPU.
*/
local_timer_setup(cpu);
/*
* OK, it's off to the idle thread for us
*/

3
arch/arm/mach-realview/Makefile
View File

@ -4,6 +4,5 @@
obj-y := core.o clock.o
obj-$(CONFIG_MACH_REALVIEW_EB) += realview_eb.o
obj-$(CONFIG_SMP) += platsmp.o headsmp.o
obj-$(CONFIG_SMP) += platsmp.o headsmp.o localtimer.o
obj-$(CONFIG_HOTPLUG_CPU) += hotplug.o
obj-$(CONFIG_LOCAL_TIMERS) += localtimer.o

10
arch/arm/mach-realview/core.c
View File

@ -596,12 +596,20 @@ static void __init realview_clocksource_init(void)
}
/*
* Set up timer interrupt, and return the current time in seconds.
* Set up the clock source and clock events devices
*/
static void __init realview_timer_init(void)
{
u32 val;
#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
/*
* The dummy clock device has to be registered before the main device
* so that the latter will broadcast the clock events
*/
local_timer_setup(smp_processor_id());
#endif
/*
* set clock frequency:
* REALVIEW_REFCLK is 32KHz

39
arch/arm/mach-realview/localtimer.c
View File

@ -14,6 +14,8 @@
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/jiffies.h>
#include <linux/percpu.h>
#include <linux/clockchips.h>
#include <asm/mach/time.h>
#include <asm/hardware/arm_twd.h>
@ -25,6 +27,20 @@
#define TWD_BASE(cpu) (__io_address(REALVIEW_TWD_BASE) + \
((cpu) * REALVIEW_TWD_SIZE))
static DEFINE_PER_CPU(struct clock_event_device, local_clockevent);
/*
* Used on SMP for either the local timer or IPI_TIMER
*/
void local_timer_interrupt(void)
{
struct clock_event_device *clk = &__get_cpu_var(local_clockevent);
clk->event_handler(clk);
}
#ifdef CONFIG_LOCAL_TIMERS
static unsigned long mpcore_timer_rate;
/*
@ -127,3 +143,26 @@ void __cpuexit local_timer_stop(unsigned int cpu)
{
__raw_writel(0, TWD_BASE(cpu) + TWD_TIMER_CONTROL);
}
#else /* CONFIG_LOCAL_TIMERS */
static void dummy_timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *clk)
{
}
void __cpuinit local_timer_setup(unsigned int cpu)
{
struct clock_event_device *clk = &per_cpu(local_clockevent, cpu);
clk->name = "dummy_timer";
clk->features = CLOCK_EVT_FEAT_DUMMY;
clk->rating = 200;
clk->set_mode = dummy_timer_set_mode;
clk->broadcast = smp_timer_broadcast;
clk->cpumask = cpumask_of_cpu(cpu);
clockevents_register_device(clk);
}
#endif /* !CONFIG_LOCAL_TIMERS */

6
arch/arm/mach-realview/platsmp.c
View File

@ -187,10 +187,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
if (max_cpus > ncores)
max_cpus = ncores;
#ifdef CONFIG_LOCAL_TIMERS
/*
* Enable the local timer for primary CPU
* Enable the local timer for primary CPU. If the device is
* dummy (!CONFIG_LOCAL_TIMERS), it was already registers in
* realview_timer_init
*/
local_timer_setup(cpu);
#endif
/*
* Initialise the present map, which describes the set of CPUs

13
include/asm-arm/smp.h
View File

@ -107,10 +107,6 @@ extern void platform_cpu_enable(unsigned int cpu);
extern void local_timer_interrupt(void);
#ifdef CONFIG_LOCAL_TIMERS
/*
* Setup a local timer interrupt for a CPU.
*/
extern void local_timer_setup(unsigned int cpu);
/*
* Stop a local timer interrupt.
@ -124,16 +120,17 @@ extern int local_timer_ack(void);
#else
static inline void local_timer_setup(unsigned int cpu)
{
}
static inline void local_timer_stop(unsigned int cpu)
{
}
#endif
/*
* Setup a local timer interrupt for a CPU.
*/
extern void local_timer_setup(unsigned int cpu);
/*
* show local interrupt info
*/